Semiconductor components must be interconnected with each other or with package leads in order to perform their intended function. Bond pads located on the semiconductor die are the sites at which such interconnections are made. Aluminum and aluminum alloys are the predominant conductive material used in chip-level metallization, i.e., as bond pads. Aluminum is a metal with a very high chemical reactivity which reacts even with pure water if a protective oxide layer is not present. Unfortunately, however, certain oxide layers frequently interfere with the efficient functioning of the semiconductor device.
During the metal patterning step the aluminum bond pads are defined and etched. Subsequently, a passivation layer is deposited on the device to protect the device throughout the testing and packaging processes. However, the protective layer is first removed from the conductive bond pads through a pad mask patterning step. The pad mask step is typically done in a plasma or dry etch chamber.
After a semiconductor device has undergone the pad mask step, residual fluorine may remain on the bond pads from the etch chemicals, for example CHF.sub.3, used in the process. This fluorine residue causes a condition referred to as "gummy pads" which is characterized by an adhesive-like oxide substance remaining on the bond pads, which substance clings to the probe tips during die testing.
The "gummy bond pads" arise because the silicon nitride layer superjacent the aluminum bond pads is typically overetched. Fluorine (F) from the etch process is deposited onto the aluminum of the bond pads, producing an AlFO.sub.3 oxide layer on the bond pads. The fluorine acts as an oxidizing agent which creates a greater than normal layer of oxide, thereby resulting in high resistivity, and consequently, low yields when probed.